Superformance Clutch Adjustment

kinglenario · #1 (**permalink**) 06-10-2007, 04:49 PM

Hi, i just had my engine rebuilt and now it's going into first a little hard. it was fine before the engine came out and the clutch engages very soon so i suspect a little clutch adjustment should cure the problem. i pulled the little cover off on the inside of the driver side wheel well and bled the system although i thought there would be an adjustment there. also i checked at the transmission and there was no adjustment. Is there an adjustment on this system?

Thanks!

Velox · #2 (**permalink**) 06-10-2007, 06:00 PM

Hi kinglenario, what SPF car number, bell housing, clutch, engine and trans do you have? Most SPF with a standard clutch fork have a hydraulic slave cylinder which is located on the driver's side of the bell housing. The slave moves an actuator rod which has two nuts jammed on it that when loosened allow movement of the actuator rod in or out (to effectively shorten or lengthen the rod). This is how the clutch is adjusted for release point, assuming that the slave is fully retracted (need to bleed the slave forcefully before adjusting rod). Make sure your hydraulic fluid is fresh and clean. Sometimes there may not be enough free pedal obtained in the fork and there may be spacer washers between the jam nuts and fork, one or more of these may need to be removed. Basically it's a standard slave cylinder clutch rod system and you need to get your car up on stands all around and get underneath to examined the bell housing and slave cylinder setup then you will see how the system is set up. Obviously it can be different if your car has a custom install, hydraulic throw-out bearing or whatever. There is a tech article on SCOF about standard SPF clutch adjusting and bleeding which is a good reference, check there for more details, and good luck!

CWizard · #3 (**permalink**) 06-10-2007, 07:27 PM

kinglenario - What Don said, plus, once you get the master and slave properly bled and adjusted, you can also change the pedal height at which the clutch engages by moving the locknuts on the threaded shaft that goes between the pedal and master cyl. You'll find these under the dash, behind the pedal. Removing the steering wheel makes access easier, unless you're young and limber. If I remember correctly, moving the locknuts toward the front gives more pedal travel before clutch engagement. Also as Don says, check out SCOF. It's an excellent source of tech info.
Good luck.

kinglenario · #4 (**permalink**) 06-11-2007, 06:26 AM

My car number is 1738. it was put together by dynamic in ohio. The engine is a Ford Motorsport 392. I'm not sure of the model Tremec.

i have been under the car and bled the slave cylinder by the bell housing, and i also bled the other slave cylinder behind the drivers side fender. The system has no air! the problem is the adjustment. The rod that comes out of the slave cylinder by the bell housing has no adjustment! there has got to be an adjustment somewhere. right now there is a huge difference between having the clutch ALL the way to the floor, or 1/8 inch from the floor.

Velox · #5 (**permalink**) 06-11-2007, 01:46 PM

Hi again, I got under the car this afternoon and took a few photos of mine to show you the adjusting rod. Maybe yours is different, but most hydraulic slaves have threads on the end of the actuating rod that allows for adjustment with the position of the jam nuts. First picture shows engine side of the rod, you can see the threads at the end, and the jam nut locked into position against the other nut that is up against the fork recess. Second picture is a side view and you can still see the threads. Third picture is from the trans side, you can see how much thread on mine is extended through the fork. Grasp the rod tightly to prevent it from turning, gently loosen the engine side jam nut, then adjust out or in as you need, bringing the inside (towards fork) nut to the position you want before you lock down the outside (towards engine) nut on the rod. Hope this helps, I would think yours should be the same or similar. Also, as CWizard noted, on the SPF there is also a pedal height adjustment under the dash.

kinglenario · #6 (**permalink**) 06-11-2007, 04:30 PM

Thanks Don but mine is totally different. there is no adjustment there. the fork looks similar to yours, but the rod is not threaded and just has a flat round end on it so that it does not pull through the fork. Could the adjustment be different than this? i have gone behind the dash before but it is such a pain i would rather not. also, i don't think it's really a pedal probem as much as a clutch adjustment problem.

Velox · #7 (**permalink**) 06-11-2007, 06:30 PM

Well kinglenario there has to be an adjustment there somewhere. Most are threaded like mine as there needs to be a way to vary the slave cylinder's rod distance from the fork. The only other thing I can think of right now is perhaps yours has an adjustable or shimmed mount for your slave cylinder. Examine closely where it bolts on and see if it is adjustable or has shims on it anywhere that can be removed or areas where shims/washers could be placed to distance the slave away from the fork. Maybe you could post a picture of how yours looks? The best answer would probably be to call Dynamic and ask them how you are to adjust this since they installed it. They presumably would have a fairly standard setup for small block clutch slave cylinders in SPF cars. The cylinder in my pic is a Raybestos sc33721 slave, fairly standard part, there's one on eBay now for like 27 bucks, so another option would be to change slave and rod to a threaded setup. Hopefully Dynamic can clarify how your car is meant to be adjusted, good luck!

jwoodard · #8 (**permalink**) 06-11-2007, 06:58 PM

It's possible that the adjustment rod adjusts from the end that's under the rubber boot on the slave cylinder. Here's a picture of a slave I had on a previous Cobra and the threaded rod fit into the piston on the slave cylinder.
http://home.flash.net/~jwoodard/Image118.jpg
Try pulling the rubber boot back some and check there for some method of adjustment.

kinglenario · #9 (**permalink**) 06-11-2007, 07:16 PM

that could be possible jim. i'm going to put it up on stands tomorrow night and i'll take a picture and let you guys know. thanks very much for your help guys!

kinglenario · #10 (**permalink**) 06-13-2007, 06:52 AM

here guys, i posted some pics. so i'm kind of at a loss here. my slave cylinder seems to not be adjustable. the rod is not threaded on either end. when i pulled the boot back a bunch of oily crap came out but it didn't seem like brake fluid. i messed around with it a little, pushing the rod back and forth, wiped up the fluid and put the boot back on. when i got back in the car, i had to pump the clutch a few times to get it to go into gear. i must have gotten air in the system somehow. do you guys think it's a bad slave cylinder?

http://www.clubcobra.com/photopost/s...to=47037&cat=9

http://www.clubcobra.com/photopost/s...size=big&cat=9

http://www.clubcobra.com/photopost/s...cat=9&size=big

http://www.clubcobra.com/photopost/s...cat=9&size=big

carmine · #11 (**permalink**) 06-13-2007, 07:15 AM

I have exactly the same problem as Kinglenario, and same slave cylinder on my superformance. I also experiance my clutch engageing at the top of pedal relise after ive pumped the pedal some 4 to 5 times then goes back to engageing at the bottom

Velox · #12 (**permalink**) 06-13-2007, 07:28 AM

Hi again, I would think there has to be a leak/pressure loss in your system, i.e. air getting in, if you had to pump the clutch several times to get the clutch to disengage. Did the fluid level in your clutch reservoir go down at all? While under the car have someone activate your pedal several times, look for consistent movement, leaks, hydraulic line defects etc. I did some reading and some slave cylinders are "non-adjusting" set up to self adjust apparently. With yours having no apparent adjustment and with hydraulic failure present, i.e. having to pump the pedal etc, I would assume there is a defect in the clutch hydraulic system, master-slave or lines. In your case, with fluid under the slave cylinder boot, you may need to rebuild or replace that I would think. You may need to check with Dynamic for the slave cylinder part number, ask them for an opinion, let us know and good luck

kinglenario · #13 (**permalink**) 06-13-2007, 08:49 AM

do you think the Raybestos sc33721 slave would bolt onto the same plate correctly?

Velox · #14 (**permalink**) 06-13-2007, 09:48 AM

Quote:

Originally Posted by kinglenario

do you think the Raybestos sc33721 slave would bolt onto the same plate correctly?

Mine is a big block (460) so may be different. I don't know if it would be the same as yours. Check the picture on eBay to see if it matches what yours looks like... (eBay item number 200118872714)